In a letter sent by Trump's attorney Alen Garten on Dec. 27, 2012, Trump threatens Carusone with a $25 million lawsuit unless he stops urging Macy's to cut ties with The Apprentice star. Garten also accuses Carusone of "mob-like bullying and coercion" and "intentionally disseminating misinformation."

Carusone and his lawyer Paul Levy continue to defend the Dump Trump petition, asserting that Carusone has done nothing but exercise his right to the First Amendment. "Donald Trump's attempt to silence me will not work. I've dealt with enough bullies and know better than to succumb to intimidation," Carusone said. "By threatening me, Trump is only reinforcing the point that we've been trying to get Macy's to recognize: that Trump's brand is consequence-free bullying and chicanery; it shouldn't be rewarded. I was also surprised to hear Trump's counsel claim that Macy's is supportive of Trump's legal action. Trump doesn't have credibility, so I don't put too much stock in the claim, but I really hope Macy's isn't encouraging these kinds of threats against its own customers."

"From the boycott of Missouri for blocking the Equal Rights Amendment to refusing to eat at Chick-fil-A for opposing gay rights, the ability to stimulate a mass 'vote with your wallet' campaign has been a key weapon for activists that has long been recognized under the First Amendment," Levy added. "Free speech trumps business expectations; even Donald Trump should know better than to bring the suit that he threatens."

Since Carusone's campaign went viral in November, more than 680,000 people have signed the petition. According to AdWeek, the department store had suffered brand damage as a result of its association with the vitriolic businessman. "Donald Trump engages in especially unpleasant, nasty and despicable behavior," the petition reads, before accusing Trump of being sexist, racist and hypocritical.

Most likely, Trump's threats to Carusone are empty. Earlier this month, he threatened to sue comedian Bill Maher for $5 million after the comedian made a joke about the mogul on The Tonight Show.